The Frequency of Antibiotic Resistance of Clinical Isolates of Clostridioides difficile to Commonly Used Antibiotics in Hospitalized Patients of Educational Hospitals of Kerman City During 2018-2020

Clostridioides difficile (C. difficile) is one of the main causes of antibiotic-associated diarrhea. It is important to find out the pattern of its antimicrobial susceptibility for reducing prevalence and also treating C. difficile infection (CDI). This study aims to investigate the antimicrobial resistance of C. difficile to commonly used antibiotics, especially vancomycin and metronidazole, as the most effective antibiotics against the bacterium.

In this descriptive study, 417 diarrheal stool samples were taken from hospitalized patients of educational hospitals of Kerman City from 2018 to 2020. The samples were cultured on cycloserine-cefoxitin fructose agar (CCFA), and suspected C. difficile colonies were isolated. Identification of the cdd-3 gene for definitive diagnosis of C. difficile was performed. Antibiotic resistance test was conducted by the disk-diffusion method using vancomycin, metronidazole, rifampin, amoxicillin-clavulanic acid, erythromycin, imipenem, ciprofloxacin, and clindamycin disks. The results were reported as numbers and percentages.

A total of 68 (16.3%) isolates of C. difficile were taken from the samples. Most C. difficile strains were susceptible to vancomycin and metronidazole, while the highest rate of resistance was related to ciprofloxacin and clindamycin. The prevalence of multi-drug resistant (MDR) strains was 77.9%.

The results of this study showed that vancomycin is still the best antibiotic for treating CDI. Also, the frequency of the isolates resistant to CDI-inducing antibiotics (erythromycin, clindamycin, ciprofloxacin) and MDR isolates was high. Therefore, the spread of resistant strains of C. difficile can be prevented by appropriate antibiotic prescription.